[PATCH] docs: document the sysfs ABI for "nohz_full" and "isolated"

[Kohei Tarumizu]

Add missing documentation of sysfs ABI for "nohz_full" and "isolated".
"nohz_full" was added by commit 6570a9a1ce3a("show nohz_full cpus in
sysfs") and "isolated" was added by commit 59f30abe94bf("show isolated
cpus in sysfs"). However, there is no documentation for these
interface.

Signed-off-by: Kohei Tarumizu <tarumizu.kohei@xxxxxxxxxxx>
---
 Documentation/ABI/testing/sysfs-devices-system-cpu | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 69c65da16dff..a9d5d87b6a41 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -666,3 +666,16 @@ Description:	Preferred MTE tag checking mode
 		================  ==============================================
 
 		See also: Documentation/arm64/memory-tagging-extension.rst
+
+What:		/sys/devices/system/cpu/nohz_full
+		/sys/devices/system/cpu/isolated
+Date:		Apr 2015
+Contact:	Linux kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx>
+Description:	information about CPU isolation.
+
+		nohz_full: (RO) the list of CPUs that are in nohz_full mode.
+			   These CPUs are set by boot parameter "nohz_full=".
+
+		isolated: (RO) the list of CPUs that are isolated and don't
+			  participate in load balancing. These CPUs are set by
+			  boot parameter "isolcpus=".
-- 
2.27.0